Method of manufacturing turbine blades



y 1933. o, A. WIBERG ET AL 0,943

METHOD OF MANUFACTURING TURBINE BLADES Filed July 9, 1931 2 Sheets-$heet 1 May 23, 1933. o.- A. WIBERG El AL 1,910,943

METHOD OF MANUFACTURING TURBINE BLADES Filed July 9, 1931 2 Sheets-Sheet 2 Patented Ma y 23,1933 i 1 i i UNITED ST TES ATE OFFICE- .osoAn ANTON WIBERG AND JOHN NoamNyor FINsPoNe, SWEDE METHODOF MANUFACTURING TURBINE BLADESI .gApplieation filed Juiye, 1931, Serial No. 549,754, and in Sweden April 29, 1930.

This inyentionrelates to the manufacture In the drawings, the invention is .illus of turbine blades of thetype having a lattrated as applied to the, 1nanufactnre;ofv erally projectingintegral root at each end. blades of the type inwhich the blade awn The object oft-he invention to render vex. onits one side and concave on its opthe nialnifactureofsuch blades as well as posite side and in which roots formed ;in-. 50

of rings or druinsof suchblades simple and tegrally with the blades areprovided which cheap. i j extend beyond the convex side of the blades, According tofthe invention the blank to It to be noted, that, of oourse,theinven-,

t be *transfornied in a blade is first subjected tion not restricted to this special type of .to one or more pressing operations so as to blades. t f

form saidprojecting roots, the surface of As blank for-the lnanufactureof blades the blade situated between said projecting according to this invention we use stcelin roots aswcll ass-m associated inner surfaces the shape of bar of appropriate section, of the rootsbe'in'gfinished by saidpressing for instance, a round bar, as shown iirtlie operation,"whereas the remaining surfaces drawings. Said bar iscut to pieces of the of the blades are onlyroughly pressed, the desiredlength. In Fig. 1 such a" piece is rough product thusobtained being then snbshown. By subjecting saicbpiece to one jected to a series of; milling 'operations and or more pressing operations it is then. given the like in order to finish said remaining theshape shownin F ig. 2, that is to say,- the sides. Beoauseof thefact that the surface, roots 22 will be produced and the surface: of the blade siti ated between the projecting 3 of the blade 1 situated between theproe portions of the roots isnioredifiicult of ac jecjting roots, which in the example shown cess than the remaining: surfaces of the should be convex, will be givenits finished blade it is evident that by thus directly. form, whereas the opposite surface. 4: of the giving this surface its finished form a conblade which in the exampleshown .should siderable simplification. of the finishing of beconcave is pressedto plane shape, as theblade may be obtained. t f shown in Fig. 3, and the remaining surfaces the accompanying drawings Figs. 19 are likewise roughly pressed. The. blade illustrate the various stages of manufacturthus pressed is then hardened and cleaned 330 mg blade according to this invention. and the burs removed. 7 The following stage Fig. lisa perspective viewof a blank piece, ofthe operation involves milling of the surand' Figs. 2, 1, 6, 8, and 9 areperspective faceft to the desired concave shape, the views of the blade as seen in itsvarious' blade. resting in saidmilling operation on stagesof development. Fig. 3 'is cross the surface 3 to enable fixing of the thicksection of: the blade shown in 2 after ness of the blade. the same time the. 8D

removal ofthei burs. Fig. 5 is a cross secedges of said surfaceare milled to straight tionfofthe blade-shown in Fig.4,andFig; forin, as shownat 5 and 6, Figs. 4 and 5 7 is a cross section of the blade according I therebydetermining thewidth of theb lade. to Fig.6. Figs. 10 and 11 are plan views, The operation nextfollowinginvolves mill- 0 partlyiin section, of an auxiliary device for ing of the surfaces'f, 8 of the roots 2 as well use in assembling the blades totforin a blade as the end snrface S) of one root, Fig. 6; to ringor drum. Figs. l and 13 are sections plane shape. The] milling of the end surcorresponding to those shown Figs. 3 and face 9 has forits object to fix the thickness 5, respectively, but relating to t a blade of .of saidroot in the longitudinal direction of modified form. r the blade so that all ofthe blades adapted to be assembled to a ring or drum may present one root of equal thickness. In said milling operation the blade is supported at the inner surface of the respective root, as indicated by the arrow'in Fig. 6.

The roots 2 are adapted to serve as distance pieces of the assembled blade ring or drum, and to this end their surface remote from the concave surface should be of a convex form corresponding to the concave surface 4 of the adjacent blade. To this end the said surface may be subjected to a milling operation, and after this operation is completed the blade will have the appearance shown in Fig. 8, where 10, 10 indicate the convex surfaces ofthe roots obtained asresult of said milling operation. After having been ground or cleaned (Fig. 9) the blade will be ready for insertion into the blade ring or drum;

The assembling of blades of the shape shown in 9 to form a. blade ring may, preferably, be effected in the following way:

The blades are placed in the relative positions they should have in the blade ring, and in effecting this placing the ground end surface 9 of the blades enables a proper relative adjustment of the blades in their longitudinal direction. In Figs. 10 and 11 auxiliary means are shown to be used in assembling the blades to form a blade ring of a radial flow turbine. The blades are placed in the desired relative positions between clamping rings 11, 12 and clamped with their ground end surfaces 9 placed against the face plate 13. Theends of the blades projecting beyond the clamping rings are then turned so to form dove-tails, a ring 14, Fig. 10, so called strengthening ring, presenting a corresponding dovetail groove being brought into engagement with the roots and sealed in thisengagement by a rolling or pressing operation. VVhe'n this strengthening ring is wider than the blades, as is usually the case, then washers in the shape of split sheet metal rings 15 are placed between the clamping rings and the blades, said washers having a thickness corresponding tov the difference in width in order to enable the removal of the blade ring from the clamping rings. After the'strengthening ring l lhas been sealed in the way described the clamping rings with the blades are turned so as to bring the ring lt into engagement with the face plate 13. After the rlamping rings havev been fixed in this position, dovetails are formed in the ground roots'new exposed, and a strengthening ring 16 is then brought into engagement with said dovetails and sealed thereto by a rolling or pressing operation.

As'already mentioned, the use of the sheet metal rings or washers 15 will allow an easy removal of the finished blade ring from the clamping rings. After removal of the washers the blade ring is ready for insertion into the turbine.

It is stated above that the surface 4 of the blade ring remote from the convex surface is pressed to plane shape, and that in. the

milling operation then following the surface is transformed to concave shape along its entire length. It is to be noted, however, that said surface may also be pressed to convex shape as shown in Fig. 12, and that in the subsequent milling operation part of the convex surface may be left intact at each end of the blade to form distance pieces, as will appear from Fig. 13.

Vhat we claim is 1.. A method of manufacturing a turbine blade which comprises subjecting a blank to a pressing action of such a nature as to form integral roots at both ends of the blank latera'lly projecting to one side thereof, to give the surface of the blank situated between said projecting roots its final shape, and to roughly formthe remaining surfaces of the blade, and subjecting the surface of the blade opposite to the surface finished by the pressing operation to a milling operation, while causing the blade to rest upon said finished surface.

2. A method ofmanufacturing a turbine blade which comprises subjecting a blank to a pressing action of such a nature as to form integral roots at both ends of the blank laterally projecting to one side thereof, to give the surface of the blank situatedbetween said projecting roots final shape, and to roughly form the remaining surfaces of the blade, subjecting the surface of the blade oppositeto the surface finished by the pressing operation to a milling operation, while causing the blade to'rest upon said finished surface, and at the same time milling the longitudinal. edges of said surface to fix the width of the blade.

A method of manufacturing a turbine blade which comprises subjecting a blank to a pressing action of such a nature as to form integral roots at both ends of the blank laterally projecting to one side thereof, to give the surface ofthe blank situated between said projecting roots its final shape, and to roughly form the remaining surfaces of the blade, subjecting the surface of the blade opposite to the surface finished by the pressing operation to a milling operation, while causing the blade to rest upon said finished surface, at the same time milling the longitudinal edges of said surface to fix the width of the blade, and milling the end surface of one root to plane form, while causing the blade to rest on the inner surface of said root in order to fix the longitudinal dimension of the root.

4. A method of manufacturing a turbine blade which comprises subjecting a blank to a pressing action of such a nature as to tween saidprojecting roots its final shape,

to give the opposite surface of the blank a plane form, and to roughly form the remaining surfaces of the blade, and subjecting said opposite surface to a milling operation, while causing the blade to rest upon said finished surface. 5. A method of manufacturing a turbine blade which comprises subjecting a blank toa pressing action of such a nature as to form integral roots at both ends of the blank laterally projecting to one sidethereof, to

give the surface of the blank situated between said projecting roots its final shape, to give the opposite surface of the blank a convex shape, and to roughly form the remaining surfaces of the blade, and subject ing said opposite surface to a milling operation, while causing the blade to rest upon said finished surface.

6. A method of manufacturing a turbine blade which comprises subjecting a blank to a pressing action of such a nature as toforni integral rootsat both ends of the blank laterally projecting to one side thereof, to give the surface ofthe blank situated between said projecting roots its final shape, to give the opposite surface of the blank a convex form, and to roughly form the remaining surfaces of the blade, causing the blade to rest upon said finished surface, and subjecting said oppositesurface toa milling operation, while leaving the end portions of the surface intact.

7. A method of manufacturing a turbine blade ring which comprises providing blades having integral roots at both ends, including milling theend surface of one root'to plane form, placing the blades between clamping rings in the desired relative position, bringing the milled end surfaces in engagement with a face plate, producing dovetails or the like on the exposed roots, bringing a strengthening ring in engagement with said dovetails, and sealing the strengthenm g ring in said engagement by a rolling or pressing operation. a i i 8. A method of manufacturing a turbine blade ring which comprises providing blades having integral roots at both ends, including milling the end surface of one root to plane form, placing the blades between clamping rings in the desired relative position, inserting washers between the clamp- 1 ing rings and the blades, bringing themilled end surfaces in engagement 'with a face plate, producing dovetails or the like on the exposed roots, bringing a strengthening ring in engagement with said dovetails and sealing the strengthening ring in said engagement by a rolling or pressing operation;

9. A method of manufacturing a turbine blade ring I which comprises providing blades having integral roots at both ends, including milling the end surface of one root'to plane form, placing the blades ;;between clamping rings in the desiredrelativeuposition, inserting split 1 sheet metal rings between the clamping rings and the blades, bringing the milled end surfaces in engagement with a; face plate, producing) dovetails or the like on the exposed roots, bringing a strengthening ring in (engagement with said dovetails, and sealing the strengthening ring in said engagement by a rolling or pressing operation.

10. A method of manufacturing a turbine blade ring which comprises providing blades having integral roots at both ends, including milling the end surface of one root to plane form, placing the blades between clamping rings in the desired relative position, bringing the milled end surfaces in engagement with a faceplate, producing dovetails or the like, on the exposedroots, bringing a strengthening ring in engagement with said doveta ls, sealing the strengthening ring in said engagement by a rolling or pressing operation, turning the clamping. rings so as to bring said strength to plane fornnplacing the blades between clamping rings in the desired relativeposition, inserting washers between the clamping rin gs and the blades, bringing the milled end surfaces in engagement with a face plate, producingv dovetails or the like on the ex posed roots, bringing a strengthening ring in engagement with said dovetails, sealing the strengthening ring in said engagement by a rolling or pressing operation, turning the clamping rings so as to bring said strengthening ring in engagement with the face plate, forming dovetails on the roots now exposed, and securing a strengthening ring to said dovetails by a rolling or pressing operation.

12. A method of manufacturing a turbine blade which. comprises subjecting a blank to a pressing action of such a nature as to form integral roots ,at, both ends of the blank laterally projecting to one side thereof, to give the surface of the blank situated between said projecting roots as well as the adjacent inner surfaces of the roots their final shape, and to roughly form the remaining surfaces of the blade, subjecting the surface of the blade opposite to the surface finished by the pressing operation to a milling operation while causing the blade to rest upon said finished surface, at the same time milling the longitudinal edges of said surface to fix the Width of the blade, and mill- 5 i'ng'the endsurface of one root to plane form, While causing the blade to rest on the inner surface of said root in order to fix the longitudinal dimension of the root.

"In testimony whereof we have signed our m names.

- OSCAR ANTON WIBERG.

JOHN NORDIN. 

